Abiotic: non-living or caused by non-living. ex. abiotic disease

Acervulus: a subepedermal, saucer-shaped, asexual fruiting body of a fungus producing condia on short condiophores.

Alternate host: a plant, other than the principal host, that a pathogen must develop to complete its life cycle

Anamorph: the asexual or imperfect reproductive stage of a fungus

Anastomosis: the union or fusion of a hypha with another resulting in the sharing of genetic material

Antheridium: male sexual organ found in some fungi

Anthracnose: a disease that appears as a black, sunken leaf, stem, or fruit lesions and caused by fungi that produce their asexual spores in a acervulus

Apothecium: an open cup- or saucer-shaped ascopcarp of some ascomycetes

Ascocarp: Sexual fruiting body of an Ascomycete bearing asci

Ascogonium: the female sexual organ of ascomycetes

Ascomycete: a group of fungi producing their sexual spores witin an asci

Ascospore: a sexually produced spore borne in a ascus

Asucs (asci): a saclike cell produced by Ascomycetes in which meiosis occurs, contains ascospores (usually 8)

Avirulent: lacking virulence or lacking the ability to cause disease

Basidomycetes: a class of fungi characterized by septate mycelium often with clam connections, forms sexual spores on a club shaped basidium

Basidiospore: a sexually produced haploid spore produced on a basidium following karyogamy and meiosis

Basidium: a club-shaped structure on which basidiospores are produced

Biological control: disease or pest control using microorganisms and other natural components of the environment

Biotype: subspecies group of organisms witin a species or race that share one or more than one character

Blight: sudden severe death of leaves, flowers, and stems

Blotch: necrotic area occuring on a leaf, stem, or fruit that is characterized by being large and irregularly shaped

Bunt: a disease of wheat and grass caused by Tilletia that replaces the grains with odorous smut spores

Callus: overgrowth of tissue (mass of large undifferentiated cells) around a wound or canker in response to injury

Canker: necrotic sunken lesion on a stem, branch, or twig of a plant

Chlamydospore: a thick walled asexual spore formed from a vegetative hyphal cell, functions as an overwintering stage

Chlorosis: a yellowing or paling of green tissue due to destruction or failure of chlorophyll production

Chronic symptoms: symptoms that appear over a long period of time

Cleistothecium: an entirely closed ascocarp, lacks a true hymenium layer and ostiole, it ruptures at maturity to release spores

Conjugation: a process of sexual reproduction involving the fusion of two gametes

Conidiophore: specialized Hyphae that produce conidia

Conidium: an asexual fungal spore produced on a conidiophore

Cyst: in fungi-an resting structure made by zoospores, in nematodes-the carcassof a dead adult females of the genus Heterodera or Globodera which may contain eggs

Damping-off: death of a seedling near the soil line, resulting in the seedling falling over

Dieback: progressive death of shoots, branches, or roots usually starting at the tip

Disease: a malfunction of host cells and tissues that results from continuous irritation by a pathogenic agent or environmental factor and leads to development of symptoms

Disease cycle: the sequence of events involved in disease development, including pathogen development, host response

Disinfectant: physical or chemical agent that fees a plant, organ, or tissue from infection

Disinfestant: an agent that kills or inactivates pathogens in the evironment or on the surface of a plant or plant organ before infection takes place

Downy mildew: A plant disease in which the sporangiophores and spores of the fungus appear as a downy growth on the lower surface of leaves and stems, fruit, etc. caused by fungi in the family Perosoporaceae